Thread-trimming device for buttonhole-sewing machines



June 16, 1925.

J. W. CONNORS THREAD TRIMMING DEVICE FOR BUTTONHOLB SEWING MACHINESFiled Dec. 26, 1924 4 Sheets-$heet 1 lnvenTor. John W. Connors byimawkJune 16, 1925. v 1,542,764 J. w. CONNORS THREAD TRlMMING DEVICE FORBUTTONHOLE SEWINGMACHINES Filed 1139.9. 26, 1924 4 Sheets-Sheet 2 UohnConnors b yiuwl Muf AIMS.

June 16 1925.

J. W. CONNORS THREAD TRIMMING DEVICE FOR BUTTONHOLE SEWING MACHINESFiled Dec. 26,

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Patented June 16, 1925.

v UNITED STATES 1 r 1,542,764 TENT OFFICE.

7 JOHN W. CONNOR-S, OF DEDHAM, MASSACHUSETTS, ASSIGNOR I'D THE REECEBUTTON HOLE MACHINE MAINE.

THREAD-TRIMMING DEVICE FOR BUTTOZNHOLE-SEWING MACHINES.

Application filed December 26, 1924. Serial No. 758,105.

To all whom it may con-am:

Be it'known that I, JOHN W. CoNNons, a citizen of the United States, andresident of Dedham, county of Norfolk, State of Massachusetts, haveinvented an Improvement in Thread-Trimming Devices for Buttonhole-SewingMachines, of which the following description, in connect-ion'with therectly from the main cam of the machine,

Other objects of the invention are to improve generally thread cuttersall as will be morefully hereinafter set forth.

In the drawings wherein I have illustrated a selected embodiment of theinvention,

, Fig. 1 is a side view of a buttonhole sewing Y machine embodying theinvention;

Fig. 2 is a plan View of the bed, frame showing the head removed andillustrating the thread cutter and its actuating mechanism. I

Fig. 3 is an under side view of the bed frame.

Fig. 4: is a fragmentary view similar to Fig.2 but showing the-cutter inthread cutting position;

Fig. 5 1s a section on the line.55, Fig. 2; Fig. 6 is a section on theline 6-6, Fig. 2;

Fig. 7 is a fragmentary front view of thev bed plate" showing thecuttenactuating mechanism. a

In the machine herein shown 1 indicates the bed frame of the machinewhich supports the usual overhanging arm or head 2 in which the needlebar 3 of the upper needle 4 reciprocates.

Situated beneath the bed plate is the under thread handling mechanismwhich, in the construction herein shown, is mounted on a rotary turret5.

The work in which the buttonhole is to formed is held in a work holdercomprising a clamp plate 6 on whichthe work is sup- [ported andworkclamps 7 which clamp the Work aganist the clam'p late 6.. This workholder is movable back and forth on the bed the buttonhble and thenbackalong the other side of the buttonhole, after which the work holder isgiven a further movement to return the work to buttonhole-cuttingposition.

8 indicates the usual buttonhole cutter. 9 indicates the usual main camwhich is situated underneath the bed plate and by which the operationsof the machine are controlled. The parts thus far described are or maybe all as usual in buttonhole sewing machines and form 110 part of thepresent invention which relates to the thread cutter for trimming thethread beneath the work and'between the latter and the clamp plate 6.This thread cutter is in the form of a swinging member 10 pivoted at 11to an extension 12of the clampplate 6, said cutter having a reentrantcutting edge 13 which co-operatcs with the shearing edge let of ashearing block 15- securcd to the clamp plate 6.

The cutter is shown in mal' posit-ion which it occupies during thestitching operation and when the thread is to be cut at the end of thestitching operation said cutter which is beneath the work, isswung tothe right Fig. 2 into the position shown in Fig. 4. Duringthis movementthe under thread which leads from the work and also the loop of upperthread leading from the under side of the work around the looper andback through the work again. are caught by the reentrant cutting edge 13and are carrled against the shearing edge 14, andare thus cut. In

"practice aguard plate is employed to cover the cutter, said guard plateforming the support on which the work restsand, being provided with anopening through which the threads extend.

16 indicates a yielding hold down which holds the cutter in shearingengagement COMPANY, or BOSTON, MASSACHUSETTS, A CORPORATION or ment bymechanism actuated from the main cam 9. Pivoted to the clamp plate 6 at17 is an actuating lever 18 which is formed with an extension 19 havinga slot 20 there in in which slot is received a pin 21 secured to thecutter. The swinging movement of the member 18 will thus give a swingingmovement to the cutter as will be obvious. The actuating member 18projects beyond the front edge of the bed frame as shown at 22and saidprojecting portion n2 is adapted to be engaged by a projection 23 risingfrom a slide 24 which is movable transversely across the bed frame. Thisslide 24 is mounted for reciprocating movement in a. guide member 25that is secured tojthedepending flange 26 of the bed frame. Theprojection 23 may conveniently have an anti-friction roll 27 thereon toreduce the frictional engagement, with the projecting portion 22 of themember 18.

The member 18 is norn'ia-lly held in its retracted position shown inFig. 2 by means of a spring 28 herein shown as apulling spring connectedat one end to the clamp plate 6 as shown at 29 and connected at itsother end to the end of an arm 30 which is secured to and extendslaterally from the member 18.

The slide 24 is shown as having a pin or projection 31 dependingtherefrom which operates in a slot 32 in one arm 33 of an elbow lever34, the latter being pivoted at 35 to the under side of the bed frame 1.The arm 36 of the elbow lever has a pin and slot connection with asliding bar 37 which extends longitudinally of the bed frame andoperates in, a slot 38 formed therein. The other end of the bar 37 ispivotally connected to a lever 39 which is pivoted to the bed frame at40 and which is adapted to be engaged and actuated by a roll 41 carriedby the main cam 9.

The lever 39 is located on the upper side of the bed frame 1 and theinner end of said lever has the depending portion 42 which extendsthrough an opening 43 formed in the bed frame, the lower end of saiddepending portion having the cam face 44 adapted to be engaged by theroll 41 as the cam 9 rotates.

The slide bar 37 is acted upon by a spring 145which tends normally tohold the parts in the position shown in Fig. 3.

The engagement of the roll 41 with the cam face .44 will swing the lever39 into the dotted line position Fig. 2, and this movement ofthe leverwill operate through the slide bar 87 and elbow lever 34 to actuate theslide 24 thereby to carry the roll 27 against the extension 22 of theactuator 18 and swing the latter to the right Fig, 2 which will operateto give the knife its th read -tri i nn1ing 'movement.

As the r911 41 Wipes ofi from the cam 44 the springs 145 and 28 willreturn the parts to their normal position shown in Fig. 2.

Sewing machines of this type are commonly so constructed that the maincam will make one complete revolution during each sewing cycle, themachine coming to rest automatically at the end of the cycle. The roll41 is so situated on the cam. 9 that it will engage the cam face 44after the sewing on the buttonhole has been completed and while the workholder is moving from stitching to buttonhole cutting position. Thetrimming of the thread will, therefore, be accomplished directly afterthe completion of the buttonhole.

Another feature of the present invention relates to means for ensuringthat the cutter will be returned to its normal position shown in Fig. 2after the cutting operation. This is accomplished by providing theprojecting end 22 of the actuating lever 18 with a depending flange 45and providing the slide 24 with an extension 46 having an up-turnedflange 47. During the time that the work holder is in stitching positionit is in the position illustrated in Fig. 2.

The movement of the work holder from stitching to bnttonhole cuttingposition is a backward movement; (which is an upward movement looking atFig. 2) and during this movement the depending flange 45 is carried intojuxtaposition to the up-turned flange 47 as shown in Fig. 4. At thistime the flange 47 is behind the flange 45 and, therefore, during thereturn movement of the slide due to the action of the spring 1-15 theupstanding flange 47 will engage the depending flange 45 and positivelyreturn the member 18 to its normal position in case the spring 28 failsto do so. Since this member 18 is connected to the cutter through thepin 20 and slot 21 the cutter is positively returned to its normalposition thus preventing danger of its sticking and remaining in itsthread-cutting position.

The swinging movement of the member 18 limited by a stop pin 51operating in a slot formed in said member,

The lever 39 is shown as adjustably connected to the slide 37. Thisadjustment is provided for by pivoting the lever to a block 52 as shownat 53 and adjustably connecting the block to the slide by means of thescrew 54. The block 52 is shown as having a slot in which the screw 54opcrates.

Vvhile I have illustrated a selected embodiment of my invention I do notwish to be limited to the constructional features shown.

I claim. i

1. In a sewing machine, the combination with a bed frame, ofwork-holding means carried thereby, stitch-forming mechanism, a main camby which the operation of the 2. In a sewing machine, the combinationwith a bed frame, of work-holding means,.

stitch-forming mechanism, a main cam by which the operation of themachine is controlled, a thread cutter carried by the workholding means,a slide carried by the bed frame and movable transversely thereof andadapted by its movement to actuate the thread cutter, and means toactuate the slide by the rotation of the main cam.

3. In a sewing machine, the combination with a bed frame, ofwork-holding means movably mounted thereon, stitch-forming mechanism, amain cam for controlling the operation of the machine and giving thework-holding means its movement, a thread cutter carried by and movablewith the work-holding means, a slide mounted on the bed frame andadapted by its movement to actuate the thread cutter, and means toactuate the slide from the main cam.

4. In a sewing machine, the combination with a bed frame, ofwork-holding means movably mounted thereon, stitch-forming mechanism, amain cam for controlling the operation of the machine and giving thework-holding means its movement, a thread cutter carried by and movablewith the work-holding means, a slide mounted on the bed frame andmovable transversely thereof, said slide by its movement actuating thethread cutter, and means to' actuate the slide from the main cam.

5. In a sewing machine, the combination with a bed frame, ofwork-holding means movably mounted thereon, stitch forming mechanism, amain cam by which the workholding means are moved on the bed frame,

a pivoted thread cutter carried by the work holding means, a slide onthe bed frame movable transversely thereof and adapted by its movementto operate the cutter, a second slide movable longitudinally of the bedframe and connected to the first-named slide, and means to actuate thesecond slide by the .cam.

6. In a sewing machine, the combination with a bed frame, ofwork-holding means movably mounted thereon, stitch-forming mechanism, amain cam by which the workholding means are moved on the bed frame, apivoted thread cutter carried by the workholding means, a slide on thebed frame movable transversely thereof and adapted by its movement tooperate the cutter, a second slide movable longitudinally of the bedframe, an. elbow lever connecting the slides, a cam lever pivotallyconnected to the second slide and having a cam surface, and a rollcarried by the maincam toengage said surface.

7, In a sewing machine, the combination with a bed frame, ofwork-holding means movably mounted thereon, stitch-forming mechanism, amain cam by which the operation of the machine is controlled, a threadcutter movably carried by the workholding means, a slide movably mountedon the bed frame, means to operate the slide in one direction from themain cam, the

.cam operated movement of the slide giving name to this specification.

JOHN XV, CONNORS.

